Newly declassified U.S. army documents reveal that two American POWs sent secret coded messages to Army intelligence after their 1943 visit to Katyn, pointing to Soviet guilt for the 1940 massacre.

After witnessing rows of corpses in the Katyn forest, on the western edge of Russia, the American POWs told Washington they believed the Nazi claims that Soviets had carried out the killings of 22,000 Polish officers.

Having seen the advanced state of decay of the bodies, the POWs concluded that the killings must have been carried out by the Soviets rather than the Nazis who had only recently invaded the area surrounding the Katyn forest.

The documents shed further light on decades of suppression of Soviet guilt within the U.S. government which began during WWII when the blame for the massacre was being pointed at Nazi Germany.

—“The killings were methodical. After the personal information of the condemned was checked, he was handcuffed and led to a cell insulated with stacks of sandbags along the walls and a felt-lined, heavy door. The victim was told to kneel in the middle of the cell, was then approached from behind by the executioner and immediately shot in the back of the head. The body was carried out through the opposite door and laid in one of the five or six waiting trucks, whereupon the next condemned was taken inside. In addition to muffling by the rough insulation in the execution cell, the pistol gunshots were also masked by the operation of loud machines (perhaps fans) throughout the night. This procedure went on every night, except for the May Day holiday.”—